The present invention relates to data transmission and reception in a wireless communication system, and more particularly, to data transmission and reception between a relay and a base station in a wireless communication system including the relay.
A relay station (RS) is a device serving as an intermediary between a base station and user equipment (UE). As illustrated in FIGS. 1A and 1B, an RS is deployed in a dead zone or at a cell boundary to effectively extend cell coverage and increase a throughput without adding a new base station or establishing a wired backhaul.
FIG. 1A shows a relay use model in which coverage can be extended using a relay. To be specific, FIG. 1A shows a case in which relays are deployed at the cell coverage boundary of a donor base station and outside the cell coverage boundary and provide service to UEs located outside the cell radius of the base station, and a case in which relays relay a signal of the base station to UEs that are located among buildings, in a building having a poor wireless environment, in a subway train, and across a cluster of buildings from the base station.
FIG. 1B shows a relay use model in which a cell throughput is improved using a relay. Relays 200-1 and 200-2 shown in FIG. 1B are located within the cell radius of the donor base station 100 and provide service of better quality to UEs located close to a cell boundary, compared to a case in which there is no relay. In other words, when there is no relay between the base station 100 and a first UE 300-1, a low transmission rate, for example, a quadrature phase-shift keying (QPSK) link, is provided to the first UE 300-1. On the other hand, when a second UE 300-2 and a third UE 300-3 are located within a relay cell radius, the relay transmits data received from the base station 100 to the second UE 300-2 and the third UE 300-3 at a high transmission rate, such as 64 quadrature amplitude modulation (QAM), so that a cell throughput can be improved.
Using relay technology, data can be transmitted between a base station and a UE in various ways. For example, a base station directly transmits data to a UE without a relay, or a relay between a base station and a UE relays data, which extends existing cell coverage and improves a throughput. As another example, an additional UE performs relay transmission between a base station and a UE, which requires autonomic constitution and management of an ad-hoc network. This transmission method is suited to support an emergency call capable of replacing communication that is impossible over an existing network.
When such a relay function is adopted in a wireless communication network, there is a change in a wireless link. That is, while two links between a base station and a UE are enough for conventional art, an added relay requires an additional wireless link. In other words, an uplink and downlink between a donor base station and a relay and an uplink and downlink between the relay and a UE should be additionally taken into consideration.
Thus far, much research has been conducted in relation to the relay technology by organizations for standardization such as long term evolution (LTE)-advanced of third generation partnership project (3GPP), Institute of Electrical and Electronics Engineers (IEEE) 802.16m, etc. However, a detailed procedure, a channel configuration method, a channel transmission method, etc. for data transmission and reception between a relay and a base station have not been suggested yet, and thus are needed.